richards



(No Model.)

S. MARTIN & J. P. RICHARDS.

ELEGTRIO ARC LAMP.

Patented Jan.9, 1883.

gy-Eausnzar. 4 J

--- Wz'inessss.

N. PETERS. PhmuLiUvognnher, wmxin mn. D. C.

UNITED STATES PATENT OFFICE.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 270,449, dated January9, 1883.

Application filed November 9, 1882. (No model.)

To all whom it may concern:

Be it known that we, SAML. MARTIN and ,JAMES F. RICHARDS, citizens ofthe United States, residing at Pittsburg, in the county of Allegheny andState of Pennsylvania, have invented certain new and uset'ullmprovementsin Electric Lamps, of which the following is a specification, referencebeing had therein to the accompanying drawings.

Our invention relates to an improvement in electric lamps; and itconsists in the adaptation of an armature through which thecarbon-holder carrying the carbon at its end passes,which armature, inaccordance with the i5 magnetic power evolved, allows the holder togradually slide down and maintain the required distance for the arebetween the carboll points, as will be fully described hereinafter.

The accompanying drawings represent our invention.

Figure 1 is aside elevation of alamp embodying ourinvention.

Figs. 2, 3, 4, 5 are detail views.

2 Letter A represents an electro-ma-gnet vertically attached to arod, B.Around the projecting end of the core bis a flat brass collar,

;, flush with the end ot' the magnet, with a groove, (1, surrounding themagnet. Through the core of the magnet is an opening for the passage ofthe carbon-holder f, that carries at its lower end the carbon point, tobe metby a similar one on a fixed and insulated rod underneath. ()n thecarbon-holderf, facing and 5 in proximity of the magnet, is an armature,h, consisting of two brass plates crossing each other and armed attheirends toward the magnet with softiron. These pieceso of soft ironare secured to the plates h by means of rivets, and serve as the meansof operating the plates h as they are drawn toward or allowed to fallaway from the magnet. In one of the brass plates of the armature is aslot into which the other, cutaway for the purpose, euters at rightangles with the former, and the armed ends of both plates are turnedtoward the magnet. The slot is slightly wider than necessary to admitthe plate to allow the position of the plates to be changed from a rightto an obtuse or an acute angle. Through both plates ot'the arma me, whenata right angle to each other, is a circular hole, i, passing throughthe point of intersection, for the carbon-holder to pass through, whichhole, when 55 the plates are inclined to an angle greater or less thanninety degrees, becomes elliptic by the two opposite sides being broughtcloser together. The carbon-holder, sliding through the hole 2' whilecircular, is therefore held fast when it ceases to be of that form,caused by a change in the relative position of the plates, and againreleased when the former status is reestablished. Being placed nearthemagnet, the armed ends of the plates are more or less drawn towardit,according to the development of the magnetic power, and when greatestthe armature approaches to the groove (1, by which itis prevented fromcoming in contact with the magnet. The effect of this approach to themagnet is a change of angles between the platcs,and consequently of theform of the hole 2' from the circular to an elliptie, the contractedsides of which grip the carbon-holder in two places and prevent it fromsliding, thus maintaining the distance be- 7 tween the carbon pointsuntil by a diininution of magnetic power by burning the carbon theplates by their own gravity recede, and thereby cause the hole 71 toreassume a more circular form and allow the carbon-holder to slidedownward, to be held again as soon as greater magnetic power againattracts the armature. Affected by the slightest change in the magneticattraction, the armature controls the carbon-holder, allows it to slidedown when necessary to restore the arc to its lost or losing brilliancy,and when restored holds it until the carbon has again been consumed torequire a nearer approach ofits points.

Having thus described our invention, we claim-- In an electric lamp, anarmature consisting of two brass plates provided with the pieces of softiron 0, and intersecting each other, and provided with a circular holeat the point of 5 intersection for the carbonholder to pass when theplates are at. an angle of ninety degrees to each other, which hole, bya change of position of the plates to a dit'terent angle, assumes anelliptic form, in which the carbonholder is suspended and prevented fromsliding down, substantially as described.

In testimony whereof we affix our signatures in presence ottwowitnesses.

SAMUEL MARTIN. JAMES F. RICHARDS. YVitnesses LOUIS MoEsER, T. F.LEmI-ANN.

